https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78379
--- Comment #36 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> ---
Results look very good.
Gfortran 7, no patch gives:
$ gfc7 -static -Ofast -ftree-vectorize compare.f90
$ ./a.out
=========================================================
================ MEASURED GIGAFLOPS =
=========================================================
Matmul Matmul
fixed Matmul variable
Size Loops explicit refMatmul assumed explicit
=========================================================
2 2000 4.706 0.046 0.094 0.162
4 2000 1.246 0.246 0.305 0.351
8 2000 1.410 0.605 0.958 1.791
16 2000 5.413 2.787 2.228 2.615
32 2000 4.676 3.416 4.622 4.618
64 2000 6.368 2.652 6.339 6.167
128 2000 8.165 2.998 8.118 8.260
256 477 9.334 3.202 9.248 9.355
512 59 8.730 2.239 8.596 8.730
1024 7 8.805 1.378 8.673 8.812
2048 1 8.781 1.728 8.649 8.789
Latest gfortran trunk with patch gives:
$ gfc -static -Ofast -ftree-vectorize compare.f90
$ ./a.out
=========================================================
================ MEASURED GIGAFLOPS =
=========================================================
Matmul Matmul
fixed Matmul variable
Size Loops explicit refMatmul assumed explicit
=========================================================
2 2000 4.738 0.048 0.092 0.172
4 2000 1.438 0.248 0.305 0.378
8 2000 1.511 0.617 1.177 1.955
16 2000 5.426 2.810 1.854 2.881
32 2000 4.688 3.314 4.357 5.091
64 2000 6.669 2.674 6.629 7.110
128 2000 9.139 3.000 9.076 9.131
256 477 10.495 3.184 10.466 10.516
512 59 9.577 2.189 9.477 9.635
1024 7 9.593 1.381 9.519 9.658
2048 1 9.722 1.709 9.625 9.785
